1. Technical Field
The present disclosure relates to nonaqueous electrolyte batteries, particularly to lithium ion secondary batteries.
2. Related Art
Nonaqueous electrolyte batteries have been put into practical use as batteries for vehicles including hybrid vehicles and electric vehicles. Lithium ion secondary batteries have been used as such on-vehicle batteries. Lithium ion secondary batteries have been required to have various characteristics: output characteristic, energy density, capacity, lifetime, and high-temperature stability. In particular, various improvements for the electrolyte solution have been attempted in order to enhance the battery life (i.e., cycle characteristic).
For example, JP-A-2012-94454 has disclosed that cyclic disulfonate is added to the electrolyte solution in order to improve the rate characteristic after the battery is preserved under high temperature. In the example disclosed in JP-A-2012-94454, a lithium manganese aluminum composite oxide is used for the positive electrode active material and the nonaqueous electrolyte solution including added dimethylene methanedisulfonate is used.
It has been known that the cyclic disulfonate is decomposed on the surface of the electrode (especially, negative electrode) to form a film. The formed film allows the battery to have a higher cycle characteristic. In particular, it has been known that the methylene methanedisulfonate (hereinafter referred to as “MMDS”) is highly effective in protecting the negative electrode.